Question

Out of $C{u}_{2}C{l}_2$, and $CuC{l}_2$ which is more stable and why?

Answer 1

In $C{u}_{2}C{l}_2$, Cu exists as Cu (I) whereas, in $CuC{l}_2$, 𝐶𝑢 exists as $Cu\left(II\right)$.

$Cu\left(II\right)$ has smaller size but greater charge i.e., it has higher charge density, due to which hydration enthalpy involved with $C{u}^{2+}\left(aq\right)$ is much more negative than that involved with $C{u}^{+}\left(aq\right)$.

This makes $Cu\left(II\right)$ i.e., $CuC{l}_2$ more stable